In many computer systems, a cursor is the interface between the user and the computer when used for command executions, graphic displays, icon selection, menu choices, spreadsheets, word processing, video games, etc. Frequently, the cursor is controlled by keys on the keyboard allowing the cursor to be moved to the desired position.
There are, however, other types of cursor-control devices that are available and commonly used. One such device is referred to as a "mouse," which is moved by the user on a table or other flat surface. Movement of the mouse in a given direction on the table causes a corresponding movement of the cursor on the computer monitor or screen. The mouse has, however, a number of disadvantages. It requires the user to move one hand from the keyboard to move the mouse. Also, there must be available a sufficiently large, flat area over which the mouse can be moved. The requirement of constantly shifting a hand from the keyboard to the mouse decreases the operator's efficiency in word processing and spread sheet applications. Moreover, the conventional mouse cannot be used by persons with certain physical disabilities in their motor functions.
There are other cursor control devices such as light pens, joy sticks, track balls and thumb wheels. However, each of these devices also requires the user to continually shift one hand between the cursor control device and the keyboard. Moreover, some of these devices are somewhat difficult to master and they frequently take several hours of practice and training before a user can become efficient in their use. Also, all of these devices are practically useless with laptop and portable computers because of the additional space their use requires.
In an attempt to overcome the inherent disadvantages of the mouse and other cursor-control devices, there have been developed systems utilizing head movement to control the cursor. An example of this type of cursor-control device is shown in U.S. Pat. No. 4,682,159 in which a headset is worn by the user, which headset contains ultrasonic receivers that pick up sound waves transmitted by a ultrasonic transmitter in the vicinity of the computer display. The sound waves are compared for phase changes, which are converted into position change data used by the computer to control the cursor. However, this ultrasonic system requires a special headset to be worn by the user and requires sufficient power to operate the ultrasonic system. Also, the user must move his or her head to move the cursor; cursor movement cannot be accomplished by eye movement alone.
There has also been a considerable amount of research conducted using the reflection of light from the eye to detect eye movement and thus allow a person to use his or her eyes to make limited selections displayed on a screen. An example of the utilization of this type of technology is shown in U.S. Pat. No. 4,950,069. Systems of this type, however, require the head to be maintained in a fixed position, and they require special hardware and software which substantially increases the cost to a point where the systems have only limited use in specialized situations, such as for the handicapped. The technology employed in U.S. Pat. No. 4,950,069 is based upon considerable research that has been done in the area of recording methods for eye movement and image processing techniques. This research is summarized in two articles published in the periodical "Behavior Research Methods & Instrumentation": Vol. 7(5), pages 397-429 (1975) entitled "Methods & Designs--Survey of eye movement recording methods"; and Vol. 13(1), pages 20-24 entitled "An automated eye movement recording system for use with human infants". The basic research summarized in these articles is concerned with accurate eye movement measurement, and is not concerned about utilizing the eye movement to carry out any other functions. In all of these eye movement recording methods, the head must be kept perfectly still. This is a serious disadvantage for the normal user.
There is, therefore, a need for a cursor control method and system which does not require use of the hands.
There is a further need for a cursor control system that utilizes eye and/or head movement to control the position of the cursor but which does not require the user to maintain the head in a fixed position.
There is also a need for a cursor control system utilizing eye movement but which can be used to communicate with the present operating system of the computer in the same manner as a conventional mouse, thus allowing use of the system with all presently available software without any modification of existing hardware.
There is also a need for a system for controlling cursor movement utilizing eye and/or head movement, which system can be produced and marketed at a cost competitive with the conventional mouse.
The objects of the invention are to fulfill all of the foregoing needs.